公开(公告)号：US08396319B2

公开(公告)日：2013-03-12

申请号：US12373969

申请日：2007-07-17

Applicant: Edward N. Pugh, Jr. ,  Nader Engheta ,  Shih-Schon Lin ,  Konstantin Yemelyanov

Inventor： Edward N. Pugh, Jr. ,  Nader Engheta ,  Shih-Schon Lin ,  Konstantin Yemelyanov

IPC: G06K9/40 ,  H04N5/202

CPC classification number: G06K9/2036 ,  G06K9/3241 ,  G06K2209/21 ,  G06T5/009 ,  G06T5/50

Abstract: Shadow is an inseparable aspect of all natural scenes. When there are multiple light sources or multiple reflections several different shadows may overlap at the same location and create complicated patterns. Shadows are a potentially good source of information about a scene if the shadow regions can be properly identified and segmented. However, shadow region identification and segmentation is a difficult task and improperly identified shadows often interfere with machine vision tasks like object recognition and tracking. A shadow separation and contrast enhancement method based on the polarization of light is provided. Polarization information of scenes is captured by a polarization-sensitive camera and the scenes are processed to effectively separate shadows from different light sources.

Abstract translation: 阴影是所有自然场景的不可分割的一面。 当有多个光源或多个反射时，几个不同的阴影可能会在同一位置重叠，并产生复杂的图案。 如果阴影区域可以正确识别和分割，阴影是有关场景的潜在的良好信息来源。 然而，阴影区域识别和分割是一项艰巨的任务，不正确识别的阴影通常会干扰机器视觉任务，如物体识别和跟踪。 提供了基于光的偏振的阴影分离和对比度增强方法。 场景的极化信息由偏振敏感摄像机拍摄，并且处理场景以有效地分离来自不同光源的阴影。

公开(公告)号：US20070280513A1

公开(公告)日：2007-12-06

申请号：US11587349

申请日：2005-04-27

Applicant: Nader Engheta ,  Edward Pugh ,  Shih-Schon Lin ,  Konstantin Yemelyanov

Inventor： Nader Engheta ,  Edward Pugh ,  Shih-Schon Lin ,  Konstantin Yemelyanov

IPC: G06K9/00

CPC classification number: G01N21/94 ,  A61B5/1172 ,  A61B5/441 ,  G01N21/21 ,  G06F19/00 ,  G06K9/00013 ,  G06K9/00033 ,  G06K9/4661

Abstract: An optical fingerprinting method extracts high quality latent fingerprints from a surface without any invasive chemical or physical contact with the examined object, and requires no cooperation of the subject. Rather than employing extraneous material, the optical properties of the latent fingerprint are used to generate one or more images with sufficient contrast to distinguish the latent fingerprint or some other deformation in the surface. The system includes a light source oriented to apply light at an angle of incidence to the surface at the position to be examined for the latent fingerprint or deformation, a camera oriented to receive light specularly and diffusely reflected from the surface and/or by the fingerprint or deformation on the surface, and a processor that performs the computation for digital contrast enhancement and/or reprojection of the recovered fingerprint image to a frontal view if necessary. The technique uses optical polarization properties to enhance the images by placing a linearly polarized filter(s) in front of the observing camera. At least two pictures of the same scene with the same lighting and view angle arrangement are taken whereby each of the pictures differ only in that the orientations of the polarization filter are different. At least two light polarization parameters for each pixel are computed from the two or more images taken with different polarizer orientations. An image with each pixel value representing the value of one of the polarization parameters or a function of the polarization parameters is generated and displayed, with some digital contrast enhancement and/or reprojection applied. The hidden latent fingerprint pattern is revealed in at least one such image with the interfering background pattern significantly suppressed.

Abstract translation: 光学指纹法从表面提取高质量的潜在指纹，而不会与被检查物体进行任何侵入性化学或物理接触，并且不需要对象的协作。 不是使用外来材料，潜在指纹的光学性质被用于产生具有足够对比度的一个或多个图像以区分潜在指纹或表面中的一些其它变形。 该系统包括光源，该光源定向成以与潜在指纹或变形的待检查位置处的表面成角度地施加光，照相机，其被定向成从镜面反射并从表面漫反射和/或指纹 或变形，以及处理器，如果需要，则将恢复的指纹图像的数字对比度增强和/或再投影执行到正面视图。 该技术使用光学偏振特性来通过在观察相机的前面放置线性偏振滤光器来增强图像。 拍摄具有相同照明和视角配置的相同场景的至少两幅照片，由此每幅照片的差异仅在于偏振滤光片的取向不同。 从使用不同偏振器取向拍摄的两个或更多个图像计算每个像素的至少两个光偏振参数。 生成并显示具有表示极化参数之一的值的每个像素值的图像或者偏振参数的函数，并且应用一些数字对比度增强和/或重新投影。 隐藏的潜在指纹图案在至少一个这样的图像中被显露，其中干扰背景图案被显着抑制。